Regulation of appetite during total parenteral nutrition

To study effects of total parenteral nutrition (TPN) on appetite, in an effort to obtain an objective assessment of hunger separated from underlying pathology, caloric intake and levels of TPN were measured in two male rhesus monkeys. TPN was found to affect appetite by reducing voluntary food intake. One monkey showed precise regulation of daily oral caloric intake and maintained stable body weight during this period. The other monkey did not show such precise regulation. When TPN was stopped, both continued suppression of oral intake for a time. Implications are discussed.